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Now let’s make use of this temperature sensor on ALIX board. First we need lm_sensors package, so let’s install it:# yum install lm_sensors

Now if you’ll run sensors-detect it won’t detect anything. We need the module called scx200_acb:# grep -i scx200_acb /boot/config-`uname -r`# CONFIG_SCx200_ACB is not set

Ok, it exists in kernel sources, but just not compiled in CentOS/RHEL kernel. Let’s compile it ourselves. It can be done on ALIX ifself (but will be slow and take time and space) or on any other CentOS machine.

First step for successful installation of CentOS (or RHEL/Fedora) on ALIX board is to use Microdrive instead of CompactFlash card, so you won’t have to worry about CF write cycles. Microdrives go now for $10-20 on eBay. Definitely worth it. I used 2.5GB Seagate ST625211CF Microdrive, but I believe any other will do too.

Then you will need regular PC and IDE to CF adapder. Connect the adapter as first hard disk and install on it Linux distribution of your choice. And yes, you can create swap partition since it’s Microdrive and not CompactFlash.

Another option is to use USB card reader instead of IDE to CF adapter or VMware instead of real PC. Or connect Microdrive to another Linux machine and use yum –installroot same way it done with Xen domU images.

Any way, after Linux is installed don’t forget to enable serial console.

Despite Geode LX800 is i586 compatible CPU and CentOS/RHEL comes with i686 kernel it will boot. The only problem I’ve noticed so far is when you try to install kernel update it will complain “package kernel-2.6.18-128.1.16.el5.i686 is intended for a i686 architecture”. Fix it by:

# echo i686-redhat-linux > /etc/rpm/platform

By the way, we can also use Voyage Linux kernel. Just copy /boot/vmlinuz-2.6.26-486-voyage and /lib/modules/2.6.26-486-voyage and create initrd image:

AMD Geoge CPU shows about 1000 BogoMIPS, comparing to Pentium III 677 MHz which has 1300 BogoMIPS. And of course 256MB RAM is more that enough for small Linux box.

Since boards are meant for embedded devices they come without VGA port, so OS installation isn’t straight forward, but not too complex either. One of Linux distribution designed especially for such devices is Voyage Linux. It’s Debian based and fits into 128MB Compact Flash card.

I used 256MB CF from old camera. Plugged it into USB reader connected to my old Linux server, ran setup script and in few minutes ALIX was ready to boot.

Voyage Linux is definitely nice distribution for small systems, comes with wireless card drivers an preconfigured for ALIX’s LEDs and temperature sensors. But since I never was Debian fan I decided to install something more Red Hat based, like CentOS or Fedora. About it in the next post.